Synonyms

impair

¹ American

[im-pair] / ɪmˈpɛər /

verb (used with object)

to make or cause to become worse; diminish in ability, value, excellence, etc.; weaken or damage.

to impair one's health;
to impair negotiations.

Antonyms:

repair

verb (used without object)

to grow or become worse; lessen.

noun

Archaic. impairment.

impair ² American

[an-per] / ɛ̃ˈpɛr /

adjective

French.

noting any odd number, especially in roulette.

impair British

/ ɪmˈpɛə /

verb

(tr) to reduce or weaken in strength, quality, etc

his hearing was impaired by an accident

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Synonym Usage

See injure.

Other Word Forms

Derived Forms

Inflected Forms

Participles

Conjugated Forms

Present

Past

Future

Etymology

Origin of impair¹

First recorded in 1250–1300; Middle English empairen, empeiren “to make worse,” from Middle French empeirer, from em- im- ¹ + peirer “to make worse” (from Late Latin pējōrāre, verb derivative of Latin pējor “worse”; cf. pejoration)

Origin of impair²

First recorded in 1820–30; from French: literally, “odd,” from Latin impār “odd, unequal”; equivalent to im- ² ( def. ) + pair ² ( def. )

Explanation

If you make bad decisions in the morning after drinking coffee, you might conclude that caffeine tends to impair your judgment. When you impair something, you damage it or make it work poorly. The root of the verb impair traces back to the Latin word pejorare, meaning “to make worse,” and that’s still what happens if you impair something. Whether it’s communication, visibility, or your marriage prospects, if you impair it, you make it worse. The word can be used for situations that describe something that has deteriorated, such as “Snow continued to impair driving conditions.”

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Vocabulary lists containing impair

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Essential English Vocabulary, List 5

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United States v. Nixon (1974)

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Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

impair impairs impaired impairing

The committee typically engages such tools if a clear market-functioning or financial-stability risk threatens to impair monetary policy, a bar that current conditions don’t appear to meet.

From The Wall Street Journal ● Aug. 4, 2026

“Gondola cars encased in digital ads, flying 26 feet overhead every 25-30 seconds would irreparably impair the vista, and the sense of calm and escape from urban life,” wrote former state parks director Ruth Coleman.

From Los Angeles Times ● Aug. 1, 2026

Over time, these cysts can impair kidney function and eventually lead to kidney failure.

From Science Daily ● Jun. 17, 2026

These man-marked players were able to impair the movement of the South Korean defenders but given the stricter refereeing on grappling in the box, we have not seen teams crowd the six-yard box much.

From BBC ● Jun. 15, 2026

With a logic problem, asking people to explain themselves doesn’t impair their ability to come up with the answers.

From "Blink" by Malcolm Gladwell

This damage impairs the ability of nerves to carry electrical messages from the brain to the rest of the body - including those needed for the precise control of muscles needed to walk.

From BBC ● Jul. 22, 2026

High blood sugar impairs immune function and narrows vessels that carry oxygen-rich blood, making it harder for skin to heal.

From Los Angeles Times ● Jun. 14, 2026

Such reactions can range from responses with “no clinical manifestations” to irritating rashes to life-threatening conditions such as anaphylactic shock, which constricts breathing and impairs motor function.

From Salon ● Apr. 4, 2026

Reasons include a person falling into a coma, a form of dementia like Alzheimer’s, head injury or a stroke that impairs their ability to think or express their wishes.

From MarketWatch ● Feb. 27, 2026

This blindness impairs us in every act of communication.

From "The Sense of Style" by Steven Pinker

Fat accumulation in the liver may also have impaired the ability of pancreatic beta cells to release insulin, contributing to higher blood sugar levels in people in cluster 5.

From Science Daily ● Jul. 28, 2026

According to the Palo Alto police department, the other driver was uninjured, neither driver was impaired and no one was cited.

From Los Angeles Times ● Jul. 28, 2026

In the corner, a visually impaired man gets up out of his chair to move his body and dance, much to the delight of staff.

From BBC ● Jul. 22, 2026

The court heard that Zambada suffered from several health conditions and would need treatment in custody, with Judge Cogan describing him as "drifting towards cognitively impaired."

From Barron's ● Jul. 20, 2026

I suggested to him that I should be allowed to go in as an interpreter just as the hearing impaired have an interpreter doing sign language.

From "Silent To The Bone" by E.L. Konigsburg

In implementing the law, the government further defined "harm" to include "significant habitat modification or degradation where it actually kills or injures wildlife by significantly impairing essential behavioral patterns, including breeding, feeding or sheltering."

From Barron's ● Jul. 10, 2026

Cedars-Sinai spokesperson Duke Helfand said the hospital would be unable to recruit and retain physicians, nurses, and specialists if the measure passed, dramatically impairing its ability to provide healthcare.

From Los Angeles Times ● Jun. 10, 2026

The longer these companies leave addictive, impairing features in place, the more plaintiffs they’ll create.

From The Wall Street Journal ● Apr. 1, 2026

“In particular, how effective drones are in impairing production and transportation of crude via the Strait of Hormuz.”

From MarketWatch ● Feb. 28, 2026

This is because the act of describing a face has the effect of impairing your otherwise effortless ability to subsequently recognize that face.

From "Blink" by Malcolm Gladwell

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023